The field of the invention is building materials and the invention relates more particularly to the building of walls or fences. Perhaps the most common wall is built from cement block which requires a substantial foundation to be dug below the wall and filled with concrete to support the weight of the cement blocks. The cement blocks must be placed by a professional mason or a skilled amateur to provide a wall that has an attractive appearance. In spite of the use of foundations, such walls frequently settle in parts and form a "stairstep" crack along the joints between adjacent blocks. Such block walls are commonly covered with a layer of stucco and this crack is visible on the exterior of the stucco. This is an especially common problem with clay soils which tend to expand when wet and contract when dried.
Other common types of fences include grape stake fences or fences made with vertical slats which are nailed to rails. Unfortunately, wood has become a scarcer and more expensive commodity. Whereas original growth redwood had excellent weathering characteristics, newer redwood does not have this same ability. Thus, when such fences are built utilizing wooden posts, such posts rather quickly rot or are eaten by termites and need to be replaced in less than 10 years. Chain link fences are very widely used but have an industrial look which is unacceptable for most residential or office developments.
Various approaches have been taken to provide walls which overcome some of the problems mentioned above. The present invention also contemplates an efficient process for coating the exterior surfaces of a foam panel and various approaches have been taken for such coating processes. For instance, U.S. Pat. No. 4,303,722 shows a process for adhering glass fibre tissue to a panel. This is accomplished by passing a tissue through a pair of rollers which impregnate the tissue with adhesive. A moving belt of release material is used to press the adhesive coated tissue onto the surfaces of the foam.
A process for making plasterboard is shown in U.S. Pat. No. 4,364,790 where a roll of reinforcing material such as paper, cardboard, metallic film, aluminum sheet, glass, cloth, etc. is placed within a layer of plaster by various methods to form a reinforced plasterboard. In U.S. Pat. No. 4,488,917, cement board is made by spreading mortar over fiber scrim in a continuous manner.
Various wall constructions are disclosed in the prior art. A noise barrier is shown in U.S. Pat. No. 4,566,558. Posts made of channel material hold panels 12. The panels include a foam portion into which various channels are embedded. The foam is covered with plastic facing and chambers are provided to hold a sound absorption material.
A wall utilizing a polystyrene bead board core having a thin concrete facing reinforced with a fiberglass open weave mesh is shown in U.S. Pat. No. 4,578,915. Vertical steel studs hold gypsum wallboard 14 on an inner surface. On the outer surface, foam panels have been coated with a fiberglass mesh which contains a thin fiberglass mesh. After the panels have been screwed to the steel studs, the joints are taped and the entire assembly is coated with a Portland Cement exterior coating.
A sound barrier fence is shown in U.S. Pat. No. 4,674,593. This sound barrier uses concrete posts which are formed with grooves. Cement panels are placed in the grooves and the space between the cement panels is filled with a foam. U.S. Pat. No. 4,899,498 is another highway sound barrier. The wall panels are made from a foamed material which is covered with a fiberglass reinforced cement composition. The panels are anchored to the ground by a helical screw anchor rod embedded in a concrete pad. U.S. Pat. No. 4,961,298 shows a prefabricated exterior panel system which also uses a plastic foam board reinforced along one surface by spaced-apart reinforcing members, such as aluminum channels. Grooves are cut into the panel and the reinforcing members are held in the grooves by an adhesive.
U.S. Pat. No. 5,129,628 shows a fence wall construction which has reinforcing flanges concealed within the plastic foam body. Lastly, U.S. Pat. No. 5,404,685 shows a foam plastic wall covered with an exterior mesh stucco coating. The panels are held in grooves in adjacent posts. The styrofoam panels are coated after they have been placed between adjacent posts.
Numerous approaches have been tried to make walls out of foam panels covered with reinforced cement. Such approaches have the advantage of a lightweight panel which nonetheless has an exterior coating which is not only strong but is fire and insect proof. The foam panels themselves are relatively weak and can be easily bent. They, thus, must be supported by some sort of substrate before being coated with a reinforced cementitious material. The coating process requires skill and, thus, the form on the jobsite must be done by skilled labor.